In a field sequential fall color display system that does not require a color filter, a backlight that is sequentially lit as “red→green→blue” is used. In typical CRTs or liquid crystal displays, the frame time is 16.7 ms, but in the field sequential full color display system, the frame time is 5.6 ms, and thus, high speed responsiveness is required.
As an indicator of the high speed responsiveness, the sum of τd and τr is exemplified. τd is the fall response time of the liquid crystal, and τr is the rise response time of the liquid crystal. To satisfy the high speed responsiveness in the field sequential full color display system, it is desired that the sum of τd and τr is less than 1.5 ms.
Currently, in the market, the liquid crystal material called a nematic liquid crystal is generally used in flat panel displays such as a TV, a monitor, a cellular phone, a smart phone, and a tablet terminal. However, since the nematie liquid crystal has a slow response speed of from about ten milliseconds to several milliseconds, improvement is demanded. Since the response speed is significantly influenced by the rotational viscosity γ1 and the elastic constant of the liquid crystal, improvement has been studied by development of novel compounds and optimization of the composition, but progress of the improvement has been slow. In contrast, in a ferroelectric liquid crystal (FLC) using a smectic liquid crystal, a high speed response of several hundred microseconds is capable. However, since the ferroelectric: liquid crystal has only two states of a bright state and a dark state, intermediate gradation display necessary for a full color display is not easy, an thus, a technique such as area gradation is used.
Among FLC, a polymer stabilized V shaped-FLC (PSV-FLC) device formed of a mixture of FLC and a monomer is a device in which a fine polymer network has been formed in a ferroelectric liquid crystal, and is capable of intermediate gradation display in addition to the high speed responsiveness which is a feature of FLC, and also has improved impact, resistance compared with FLC in the related art (for example, refer to PTL 1).
In addition, in a composite material of a nematic liquid crystal and a polymer, if 70% by mass or greater of a polymerizable compound is added to a nematic liquid crystal medium, a high speed response of several tens of microseconds is obtained, but if a drive voltage exceeds about 80 V, it is not suitable for practical use, and effective birefringence becomes an order of magnitude or greater lower than the liquid crystal birefringence used, and thus, the transmittance of a device is reduced. On the other hand, a polymer-stabilised (PS) or a polymer-sustained alignment (PSA) display which mainly induces pretilt by forming a fine projection structure obtained by polymerizing or cross linking in the glass substrate interface by UV photopolymerization with applying or without applying a voltage after 0.3% by mass or greater and less than 1% by mass of one or more types of polymerizable compounds is added to a liquid crystal medium has been proposed (for example, refer to PTLs 2 to 6).
However, even in these devices, there was room for improvement in terms of high speed responsiveness. In particular, regarding high speed response of the rise speed of a liquid crystal display apparatus, various techniques such as viscosity reduction of a liquid crystal composition, increasing dielectric constant, elastic constant reduction, and imparting a pretilt angle, or improvement of a driving method such as an overdrive method, but regarding the fall speed, effective technique other than viscosity reduction of a liquid crystal composition has not been found at present, and thus, improvement is demanded.